Radio telephone system



March 19, 1929. E, E, CLEMENT 1,706,380

I RADIO TELEPHONE SYSTEM Original Filed Sept. 26, 1924 5 Sheets-Sheet 1 March 1929- E. E. CLEME NT I RADIO TELEPHONE SYSTEM Original Filed Sept. 26, 1924 3 Sheets-Sheet l iabflw March '19, 1929. E CLEMENT 1,706,380

RADIO TELEPHONE SYSTEM Original Filed Sept. 26, 1924 3 Sheets-Sheet 3 Patented Mar. 19, 1929.

UNITED STATES 1,706,380 PATENT OFFICE.

EDWARD E. CLEMENT, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO ED- WARD F. COLLADAY, OF WASHINGTON, DISTRICT OF COLUMBIA.

RADIO TELEPHONE SYSTEM.

Original application .filed September 26, 1924, Serial No. 740,113. Divided andthis application filed February 19, 1926.

My invention relates to systems of communication, and particularly to telephone and radio systems. The present application is a division of my prior copending appli-- cation, Serial No. 740,113, filed September 26, 1924, patented March 16, 1926, No. 1,577,107. The present invention has for its main object the provision of centralized maintenance and control through the centralization of the source of power or energizing current for the service units. An-' other object is to provide means for extending centralized power through a system in: cluding subcenters such as private branch exchange systems, and central radio receiving stations in apartment houses, hotels and the like. Other objects of the invention will be apparent from the following specification and the drawings accompanying the same.

My invention is illustrated in the accompanying drawings, in which:

Fig. 1 is a diagram showing a general system embodying the same. v

Fig. 2 is a schematic diagram of a private branch exchange system with radiophone receivers at the subscribers stations supplied w1th energizing current from a common source secondary to a centralized source at the main exchange.

Fig. 3 is a more detailed circuit diagram of the system of Fig. 2.

Fig. 4 is a fragmentary circuit diagram of all modification of the charging system of Fig. 5 is a further modification of the charging system of Fig. 3 using a local generator.

Fig. 6 is a further modification of the system of Fig. 3 with local generation at the private branchv exchange station taking power supply over the phantom circuit.

Referring to Fig. 1, 1, 2 and 3 represent telephone subscribers stations connected by wires 4, 5 and 6 to the central telephone ex-' change 7, constituting the distributing center for the area in which local subscribers -1, 2, 3, etc. are located. Superposed upon this telephone system is a radiophone system comprising a central station 8 and subscribers stations 1, 2*, 3, etc. The central radio station or exchange is provided with switchboards and a complete broadcasting equipment, and the subscribers stations 1, 2, 3, etc, are provided with receiving in- Serial No. 89,409.

struments all standardized for the same wave length, and adapted to respond to the waves radiated from the central station 8. The interrelation between the telephone system and the radiophone system is by means of physical connections indicated at l", 2,

and 3 at the subscribers stations, and mul- 'a telephone exchange, is not only provided with broadcasting equipment for its subscribers, but alsowith radio receivers adtained and operated by or under the direction of the telephone organization itself. By means understood in the art, messages received at the radio central stations are relayed on their respective standard wave lengths to the local subscribers.

In Fig. 2, I show an arrangement in which the idea of supplying battery current over wires to the radiophone subscribers is applied to private branch exchange systems, in which certain of the trunks T T, T", and T leading from the main exchange M to the PBX station are phantomed With a charging circuit or circuits for storage batteries such as A and B which act as a common source of current supply for the radiophones RP RP etc. associated respectively with the private branch exchange, subscribers telephone sets T T etc. The batteries A and B are the .A and B batteries, respectively, for the subscribers radiophone sets and are connected to the sets through the three bus wires 191,192 and 193. These'batteries A and B are arranged to be charged from the central oflice batteries A and B, respectively, over separate phantom circuits, or they may be alternately connected for charging to a single phantom circuit.

A more detailed circuit'diagram of the arrangement for charging the private branch exchange batteries each over a sepaside terminals of the winding 195 of a repeating coil 196, and in the PBX station at the outside terminals of the winding 197 of a repeating coil 198. The winding 199 of the repeating coil 196 is connected through a cut-off jack 200 to a. drop signal 201 at the main telephone station, while at the PBX station the coil 202 is similarly connected through a cut-off jack 203 to the drop signal 204. To facilitate the passage of voice current through the trunk from 'ack to jack, the repeating coils are bridge by telephone condensers 205 in the usual manner. At the main exchange the trunk side 195 of the repeating coil 196 is tapped at the middle and connected through a conductor 206 and switch 207 to the plus terminal of the charging battery A the minus terminal of which battery is grounded at the main exchange. Similarly a conductor 208 connects the middle of the trunk side of the repeating coil at the PBX station through a switch 209 to the plus terminal of the battery A", the minus terminal of which battery is grounded at the PBX station. The

trunk T and its terminal apparatus is the same as the trunk T and has phantomed on it a charging circuit for the battery B which circuit is connected to the battery at the PBX station by way of the conductor 210 leading through switch 211 and conductor 212 to the plus terminal of the battery B the minus terminal of which is grounded as shown. At the main station M the phantom circuit is connected with the charging battery B by the conductor 213 which leads from the middle point of the trunk side of the repeating coil through the switch 214 to the plus side of the battery B, the minus side of which is grounded. Thus, the batteries A and B are connected to separate charging batteries A and B, respectively, at the main station over separate grounded phantom circuits, one on the trunk T and one on the trunk-T. The primary sources A and B at the main exchange are of sufficient voltage to affect proper charging of their respective secondary batteries A and B The common-battery supplybusses 191, 192 and 193 are the same as those of Fig. 2, and so are multiplied to the battery consuming elements in the radio receivers. For example, where a detector tube or sin le tube set is used as indicated in Fig. 3, the filament and supply leads 216- and 217 are connected to the busses 191192, respectively, while the plate circuit conductor 218 is connected to the bus 193, the plate circuit return being effected through the filament lead 217 to the middle of common bus 192 as is' usual where a local set of batteries is used. To keep radio frequency currents ofi the busses 192 and 193 a radio frequency by-pass condenser 219 is connected as shown.

Where only one charging circuit is avail able the circuit arrangement of Fig. 4 may be used inwhich is shown the single phantomed circuit imposed on the trunk T arranged to be switched in circuit with the battery A and generator A or'the battery" B and generator B according to which battery is to be charged. In this ar rangemen-t the plate battery B is shown tapped at an intermediate point to supply detector voltage to the bus 193, while the fourth bus 220 is led from the extreme positive' terminal for supplying plate voltage where amplifier tubes are used.

Fig. 5 shows a further arrangement for supplying current from the main station in which the primary energy is supplied over the trunk line T in the form of alternating currentof superaudio frequency which"1nay or may not be modulated with audio signals but which is transformed into the proper form of energy for charging the secondary batteries A and B through a suitable high frequency'motor 221 and a-pair of generators 222 and 223 driven thereby.

In Fig. 6 is shown a further modification of the idea of charging over a phantom circuit in which the batteries are charged by a pair of local generators 224 and 225 driven by a motor 226 supplied with power over the phantom circuit from a source 227 at the main station.

The word radiophone when used herein means a radio telephone instrument.

What I claim is:

1. In a broadcasting system, a main station, a lurality of subscribers, substations, means or receiving radio waves at each substation, said means including thermionic tubes having filament and plate circuits requiring current at different voltages for their supply, a plurality of local current supply busses common'to a group of said substations, part of said busses being appropriated to the filament circuits ant part of said busses being appropriated to said platecircuits, and so connected at the several subscribers stations, trunk wires extending from the main station to a point in proximity to the group of substations served by busses, means at the main station for supplying current said trunk at different voltages suitable for the plate and. the filament circuits respectively, and means connected to said trunk circuit on the one side and the respective pairs of busses on the other side adapted to receive the currents transmitted from the central station and to selectively transmit the same over the appropriate bus circuits to the terminals of the respective filament and plate circuits of the thermionic tubes in the receiving sets at the several subscribers stations in the associated group served by said busses.

2. The broadcasting system described in claim 1, in which the means for receiving current over the trunk wires and for selectively directing the same overthe bus wires, consist in a plurality of accumulators of suitable capacity and voltage which supply the filament circuits and the plate circuits respectively of the subscribers instruments.

3. The broadcasting system described in claim 1, in which the trunk wires from the central station and the bus wires extending to the different subscribers in the local group all terminate at a branch exchange, with means whereby an attendant in the branch exchange may supervise and control the reception of radio waves at the subscribers substation independently of said bus Wires.

l. The broadcasting system described in claim 1, in which the trunk wires from the central station and the bus Wires extending to the subscribers local group of substations are both connected to 'a branch exchange, with. means whereby an attendant at said branch exchange may control and supervise the current connection between the trunk wires and the bus Wires and the reception of radio Waves by the subscribers receiving sets, respectively.

5, The broadcasting system described in claim 1, in which the means for receiving current from the central station over the trunk wires and directing the same selectively over the bus 'wires, comprise a plurality of storage batteries of suitable voltages and capacity to carry the load of subscribers stations in parallel, one battery carrying the filament load and another battery carrying the plate load, for energy supply only, whereby charging current may be sent from the central station over the trunk wires for a determinate time and at a determinate rate to accumulate energy in prop-- er quantity to carry the load of the receiving sets at a rate and for atime determined by the receivers, and independent of the conditions of charging.

6. In a broadcastlng system, a main telephone exchange station, a plurality of subscribers substations, means for transmitting radio waves to the substations, means at the substations for receiving said radio waves, a set of current supply busses common to a group of said substations, a telephone trunk circuit extending from the said main station to said busses, a plurality of storage batteries of different voltages for supplying current throu h said busses to the receiving means at di erent voltages, means at the main station for supplying current to said trunk at dilferent voltages sufficient to charge said difi'erent batteries at difierent times, and means for connecting the dilirent batteries to the trunk circuit at different times. i

In testimony whereof I hereunto aiiix my signature.

EDWARD E. CLEMENT. 

